Dentist s chair



I 2 sheetsfiheet 1. E B U R R I T T'.

- Dentists Chair. No. 228,979. Patented June 22,1880.

. HLL Ju N PETERS, PHDYWLITHDQRAFHEE WASHiNGTDN, D C.

4 mums-she t 2. E B U R RI T T Dentists Chair.

Patented June 22 I880.

' To all whom 1t may concern:

UNITED STATES PATENT O-riuca.

ELIHU BURRITT, OF ELGIN, ILLINOIS.

DENTISTS CHAIR.

SPECIFICATION formingpart of Letters Patent No. 228,979, dated June 22, 1880.

' Application filed June 30, 1879.

Be it known that I, ELIHU BURRITT, of Elgin, in the county of Kane and State of Illinois, have invented certain new and useful Improvements in Dentists Chairs, of which the following is a specification.

My invention relates to a dentists chair having its body, back, foot-rest, and head-rest capable of adjustment, and adapted to the varying circumstances under which it is required to operate.

The object of the first part of my invention is to mount the body of the chair upon an upright moving column or support vertically ad- 1 justable in a suitable base and capable of bein g automatically locked at any desired height. This is attained by mounting the chair-body on an endwise-moving column, acting upon which are two foot-levers and an automatically-actin g detent.

The other parts of my invention relate to the manner in which I regulate the tipping or rocking backward and forward and the manner of adjusting the upholstered back.

1 do not claim the manner of revolving the chair-body as set forth in this specification as new, but that the revolving movement can be applied as hereinafter described.

To the back of the chair a head-rest of any ordinary description can be applied. To the seat-frame a foot-rest can be attached in any ordinary and well-known manner.

The accompanying drawings represent my improvements as embodied in a dentists chair in the best way now known to me. Obviously, however, some of these improvements may be used without the others and in chairs different from the one shown in the drawings.

Figure 1 represents the side elevation of dentists chair embodying my improvements, with the base partially broken away. Fig. 2 is aplan section taken on the line a: as, Fig. 1. Fig. 3 is a longitudinal section taken on line y y, Fig. 2, showing the mechanism for raising the chair. Fig. 4 is a detail sectional view taken on the line 2 2, Fig. 2, showing the mode of lowering the chair. Fig. 5 is a detail section of the vertically-moving column. Fig. 6 is a detail section taken on the line 22 c, Fig. 1, showing the locking device. Fig. 7 is a detail view of the adjustable back K. Fig.

8 is a detail sectional view of the foot-rest. Fig. 9 is a rear elevation.

The base A is a circular iron casting with a flange, a, upon the outside of it. The upper base, B, rests upon the flange a". The screw F, for securing the base B from revolving, passes through it. The chair can be secured in any desired revolving position by the screw F, which is intended to be operated with the foot.

A lifting-lever, (J, is pivoted to the bolt 1), and has its inner end adapted to engage with the teeth 0 during the operation of lifting the chair-body.

By pressing down with the foot upon the outer end of the lever G the point is brought in contact with one of the teeth 0', and the chair-body can be elevated one tooth and securely held by the detent l), which is made to automatically engage with the teeth a by the spring 0. The coiled springf, wrapped around the bolt 1) and secured to the lever 0, causes it to disengage from the teeth 0 and its outer end to resume its elevated position.

The lever D, for lowering the body of the chair, is pivoted loosely to the bolt 8), and pivoted to the inner end of said lever D is a dog, a, which has a weighted end, (1. which keeps it disengaged from the teeth d, while the outer end of the lever D is held in an elevated position by the coiled spring f.

By pressing down with the foot upon the outer end of the lever D the pivoted dog a is made to engage with the detent b and disengage the same from the teeth d, which allows the weight'of the chair-body to rest upon the point of the dog a. The depressed end of the lever D is allowed to rise under the foot of the operator until the detent b arrests the descent of the column E by engaging with the next tooth above the one in contact with the dog a. After the detent b has secured the column E from descending, the spring f causes the lever D to assume its proper position, and the weighted end a of the dog a causes it to dis engage from the teeth d until the lever is again used to lower the chair.

The chair-body H is pivoted to the upright column E at the lugs g, and is secured in any desired reclining position by the foot-lever G tightening the friction-joint g on the rod h,

which is pivoted to the chair-body at the lugs h. Upon the rod h are two loosely-coiled spiral springs, i and i. In reclining or tipping the chair backward the lower spiral spring comes in contact with the friction-joint g, and as the chair body H moves backward the spring is gradually compressed, allowing the chair-body to go backward as far as the rod h will allow it without any jarring sensation to the patient in the chair. In tipping the chairbody forward the upper spiral spring is compressed between the lugs h and the frictionjoint 9, and serves as a fender to let the seatframe assume a horizontal position easily.

To the seat-frame H and back L are attached arms 0, of ordinary construction.

The adjustable upholstered back K is secured in any desired position by a bolt passing through the slots in the links 0 0. Upon the end of the bolt is a thumb-screw, f, which compresses the links 0 0 against the two lugs jon the back-frame, and holds the links a a and adjustable back K securely.

A foot-rest, I, constructed in any ordinary manner, is bolted to the seat-frame H. At the outer end of the foot-rest I a supplemental foot-rest, J, of any ordinary construction can be attached.

What I claim as new, and wish to secure by Letters Patent, is

1. The combination of two foot-levers, O and D, the weighted dog a, and automatic detent b, acting upon a toothed or racked column, E, provided with two sets of teeth, as shown, substantially as herein set forth and described, for the purpose specified.

2. The combination of a rod, h, hinged to the chair, seat-frame H, two' loosely-coiled spiral springs, i and 2', upon the rod h, a friction-joint, g, attached to the plate on top of 4.0

the elevating-column E, and the foot-lever G, substantially as herein set forth and described, for the purpose specified.

3. The combination of the back-frame L, the

lugs thereon, the bolt, the thumb-nut f, the 

